1. Field of the Invention
The present invention generally relates to communication control methods and communication apparatuses, and more particularly to a communication control method for controlling a real-time network facsimile communication based on ITU-T Recommendations T.38 between a communication apparatus and another apparatus via a packet network, and to a communication apparatus which employs such a communication control method.
2. Description of the Related Art
The ITU-T Recommendations T.38 for exchanging packetized T.30 signals in a packet network were established in April 1999. By utilizing this T.38 communication technique, it has become possible to make a capacity exchange between terminals via the packet network and to guarantee real-time communication.
Various manufacturers have developed communication apparatuses in conformance with the ITU-T Recommendations T.38 by interpreting the Recommendations T.38. Ideally, if the communication apparatuses are in conformance with the Recommendations T.38, it should be possible to positively carry out communications among the communication apparatuses, regardless of the manufacturers of the communication apparatuses.
However, in actual real-time network facsimile communications, there were problems in the mutual connection of the communication apparatuses depending on the various attributes of the communication apparatuses. That is, the communication is carried out correctly in some cases but not in other cases, depending on the attribute of the communication apparatus of the other party (at the other end), for example, such as the manufacturer, the model and the version of the communication control program of the communication apparatus of the other party.
Ideally, each manufacturer should develop the communication apparatus conforming to the ITU-T Recommendations T.38 by strictly interpreting the Recommendations T.38, and confirm the mutual connection with communication apparatuses manufactured by other manufacturers, so that the above described problem in the mutual connection can be prevented. But in actual practice, such measures are difficult to achieve.
A Japanese Laid-Open Patent Application No.2001-309112 proposes a network facsimile apparatus which varies the amount of data to be transmitted to another apparatus which is of the other party and is in conformance with the Recommendations T.38 for carrying out a real-time network facsimile communication via a packet network, depending on the terminal type, that is, whether the other apparatus is a packet network direct correction type real-time network facsimile apparatus (IAF: Internet Aware Fax) or a gate way apparatus which relays a real-time facsimile communication between a G3 facsimile apparatus in a telephone network and the network facsimile apparatus.
But since the technique proposed in the Japanese Laid-Open Patent Application No.2001-309112 simply varies the amount of data to be transmitted depending on the terminal type, it is impossible to flexibly cope with the delicate differences that actually exist in the other apparatus of the other party during the control operation of the real-time network facsimile communication of the other apparatus, caused by the attribute of the other apparatus, such as the manufacturer, the model and the version of the communication control program of the other apparatus. As a result, there was a problem in that the certainty of the real-time network facsimile communication via the packet network is insufficient.